Scott Penrose

Arduion Pull up resistors

Scott Penrose is a perl hacker with an interest in home automation. He has been playing with electronics since he was old enough to burn his fingers with a soldering iron.

Don't use them. It is built into most chips, but you have to enable it. (works Arduino AVRs; Teensy)

Older versions of arduino you simply did:

 pinMode(4, INPUT);
 digitalWrite(4, HIGH);

News versions

  pinMode(4, INPUT_PULLUP);

  • Arduino